Abstract
In this chapter we will discuss the construction and the use of simplified models for DM searches at the LHC. First we are going to describe the philosophy of simplified models in relation to the EFT approach and to complete new physics models. Then we are going to list the set of benchmarks models which have emerged as the most common ones in the recent literature. Finally we are going to summarize results obtained with these models, without entering into details about LHC searches, implementation of the models for experimental analyses, or recasting of existing bounds.
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Notes
- 1.
Constraints on BSM models from CP and flavour violating observables are very strong, and the energy scale at which new physics may show up must be larger than tens of TeV in the best case, if the flavour structure of the model is generic. Minimal Flavour Violation is a way to reconcile these constraints with possible new physics at the TeV scale [7]. The basic idea is that the structure of flavour changing interactions must reproduce that of the SM. The SM is invariant under the flavour group \(\mathcal {G}_F = \mathrm{SU}(3)_q\times \mathrm{SU}(3)_u \times \mathrm{SU}(3)_d\), except from a small breaking associated to the Yukawa matrices \(Y_u\) and \(Y_d\). The invariance is restored if these matrices are regarded as “spurions” with transformation law \(Y_u\sim (3,\bar{3},1)\) and \(Y_d\sim (3,1,\bar{3})\). Imposing MFV amounts to requiring that new physics is invariant under \(\mathcal {G}_F\).
- 2.
At the energy scales involved at particle colliders, the valence quarks are practically massless, thus their helicities coincide with their chiralities. Vector and axial vector Lorentz bilinears can be written respectively as the sum and the difference of bilinears made up with L-handed or R-handed quarks. Since the helicity is a physical observable, the total cross section can be decomposed in terms of cross sections with given initial helicity states, and their interference term vanishes. Since the latter is the only difference that could arise between the cross sections for the vector or axial vector quark current, the two are practically identical.
- 3.
The expansion in terms of Wigner d-functions has the advantage, with respect to the standard one in terms of Legendre polynomials, that the matrix element is expanded in the basis of helicity states of the particles, instead that considering total spin states.
- 4.
The unitarity criterion proposed above deals with the diagonal matrix elements \(\mathcal {M}_{ii}^J\), in which the initial and final states are equal. It can be adapted as well to the case of off-diagonal matrix elements, by restricting to the \(2\times 2\) subspace spanned by the states \(\psi \bar{\psi }\) and \(Z'_L Z'_L\), and noticing that for \(s\rightarrow +\infty \) only the off-diagonal elements survive, and hence the eigenvalues of the matrix become equal to the off-diagonal element.
References
J. Abdallah et al., Simplified models for dark matter and missing energy searches at the LHC, arXiv:1409.2893
S. Malik, C. McCabe, H. Araujo, A. Belyaev, C. Boehm, et al., Interplay and characterization of dark matter searches at colliders and in direct detection experiments, Phys. Dark. Univ. 9–10, 51–58 (2015), arXiv:1409.4075
J. Abdallah et al., Simplified models for dark matter searches at the LHC. Phys. Dark Univ. 9–10, 8–23 (2015), arXiv:1506.03116
D. Abercrombie et al., Dark matter benchmark models for early LHC run-2 searches: report of the ATLAS/CMS dark matter forum, arXiv:1507.00966
G. Busoni et al., Recommendations on presenting LHC searches for missing transverse energy signals using simplified \(s\)-channel models of dark matter, arXiv:1603.04156
A. De Simone, T. Jacques, Simplified models vs. effective field theory approaches in dark matter searches, Eur. Phys. J. C 76(7), 367 (2016), arXiv:1603.08002
G. D’Ambrosio, G.F. Giudice, G. Isidori, A. Strumia, Minimal flavor violation: an effective field theory approach. Nucl. Phys. B 645, 155–187 (2002), arXiv:hep-ph/0207036
M.J. Dolan, F. Kahlhoefer, C. McCabe, K. Schmidt-Hoberg, A taste of dark matter: flavour constraints on pseudoscalar mediators. JHEP 03, 171 (2015), arXiv:1412.5174. [Erratum: JHEP 07, 103 (2015)]
P. Agrawal, M. Blanke, K. Gemmler, Flavored dark matter beyond minimal flavor violation. JHEP 10, 72 (2014), arXiv:1405.6709
D. Racco, A. Wulzer, F. Zwirner, Robust collider limits on heavy-mediator dark matter. JHEP 05, 009 (2015), arXiv:1502.04701
G. Isidori, Y. Nir, G. Perez, Flavor physics constraints for physics beyond the standard model. Ann. Rev. Nucl. Part. Sci. 60, 355 (2010), arXiv:1002.0900
F. Kahlhoefer, K. Schmidt-Hoberg, T. Schwetz, S. Vogl, Implications of unitarity and gauge invariance for simplified dark matter models. JHEP 02, 016 (2016), arXiv:1510.02110. [JHEP 02, 016 (2016)]
T. Jacques, K. Nordström, Mapping monojet constraints onto simplified dark matter models. JHEP 06, 142 (2015), arXiv:1502.05721
A.J. Brennan, M.F. McDonald, J. Gramling, T.D. Jacques, Collide and conquer: constraints on simplified dark matter models using mono-X collider searches, JHEP 1605, 112 (2016), arXiv:1603.01366
M. Chala, F. Kahlhoefer, M. McCullough, G. Nardini, K. Schmidt-Hoberg, Constraining dark sectors with monojets and dijets. JHEP 07, 089 (2015), arXiv:1503.05916
M. Duerr, F. Kahlhoefer, K. Schmidt-Hoberg, T. Schwetz, S. Vogl, How to save the WIMP: global analysis of a dark matter model with two s-channel mediators, JHEP 1609, 042 (2016), arXiv:1606.07609
M. Fairbairn, J. Heal, F. Kahlhoefer, P. Tunney, Constraints on Z’ models from LHC dijet searches, JHEP 1609, 018 (2016), arXiv:1605.07940
R. Barbieri, G. Isidori, J. Jones-Perez, P. Lodone, D.M. Straub, \(U(2)\) and minimal flavour violation in supersymmetry. Eur. Phys. J. C 71, 1725 (2011), arXiv:1105.2296
R. Barbieri, D. Buttazzo, F. Sala, D.M. Straub, Flavour physics from an approximate \(U(2)^3\) symmetry. JHEP 07, 181 (2012), arXiv:1203.4218
T. Lin, E.W. Kolb, L.-T. Wang, Probing dark matter couplings to top and bottom quarks at the LHC. Phys. Rev. D 88(6), 063510 (2013), arXiv:1303.6638
M.R. Buckley, D. Feld, D. Goncalves, Scalar simplified models for dark matter, Phys. Rev. D 91, 015017 (2015), arXiv:1410.6497
M. Duerr, P. Fileviez Pérez, J. Smirnov, Scalar dark matter: direct vs. indirect detection. JHEP 06, 152 (2016), arXiv:1509.04282
C. Englert, T. Plehn, D. Zerwas, P.M. Zerwas, Exploring the Higgs portal. Phys. Lett. B 703, 298–305 (2011), arXiv:1106.3097
C. Englert, A. Freitas, M.M. Mühlleitner, T. Plehn, M. Rauch, M. Spira, K. Walz, Precision measurements of Higgs couplings: implications for new physics scales. J. Phys. G 41, 113001 (2014), arXiv:1403.7191
ATLAS Collaboration, Sensitivity to New Phenomena via Higgs Couplings with the ATLAS Detector at a High-Luminosity LHC. Technical report ATL-PHYS-PUB-2013-015, CERN, Geneva, October 2013
M. Papucci, A. Vichi, K.M. Zurek, Monojet versus rest of the world I: t-channel models, JHEP 1411, 024 (2014), arXiv:1402.2285
N. Weiner, I. Yavin, UV completions of magnetic inelastic and Rayleigh dark matter for the Fermi Line(s). Phys. Rev. D 87(2), 023523 (2013), arXiv:1209.1093
M.T. Frandsen, U. Haisch, F. Kahlhoefer, P. Mertsch, K. Schmidt-Hoberg, Loop-induced dark matter direct detection signals from gamma-ray lines. JCAP 1210, 033 (2012), arXiv:1207.3971
ATLAS Collaboration, G. Aad et al., Search for dark matter candidates and large extra dimensions in events with a jet and missing transverse momentum with the ATLAS detector. JHEP 04, 075 (2013), arXiv:1210.4491
J. Goodman, M. Ibe, A. Rajaraman, W. Shepherd, T.M. Tait et al., Constraints on dark matter from colliders. Phys. Rev. D 82, 116010 (2010), arXiv:1008.1783
M. Jacob, G.C. Wick, On the general theory of collisions for particles with spin. Ann. Phys. 7, 404–428 (1959). [Ann. Phys. 281, 774 (2000)]
N.F. Bell, Y. Cai, J.B. Dent, R.K. Leane, T.J. Weiler, Dark matter at the LHC: effective field theories and gauge invariance. Phys. Rev. D 92(5), 053008 (2015), arXiv:1503.07874
N.F. Bell, Y. Cai, R.K. Leane, Mono-W dark matter signals at the LHC: simplified model analysis. JCAP 1601(01), 051 (2016), arXiv:1512.00476
U. Haisch, F. Kahlhoefer, T.M.P. Tait, On mono-W signatures in spin-1 simplified models, Phys. Lett. B 760, 207–213, (2016), arXiv:1603.01267
B.W. Lee, C. Quigg, H.B. Thacker, The strength of weak interactions at very high-energies and the Higgs Boson mass. Phys. Rev. Lett. 38, 883–885 (1977)
B.W. Lee, C. Quigg, H.B. Thacker, Weak interactions at very high-energies: the role of the Higgs Boson mass. Phys. Rev. D 16, 1519 (1977)
T. Jacques, A. Katz, E. Morgante, D. Racco, M. Rameez, A. Riotto, Complementarity of DM searches in a consistent simplified model: the case of Z, JHEP 1610, 071 (2016), arXiv:1605.06513
N.F. Bell, Y. Cai, R.K. Leane, Dark forces in the sky: signals from Z’ and the dark Higgs, JCAP 1608, 011 (2016), arXiv:1605.09382
S. Weinberg, The Quantum Theory of Fields.Volume 2: Modern Applications (Cambridge University Press, Cambridge, 2013)
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Morgante, E. (2017). Simplified Models. In: Aspects of WIMP Dark Matter Searches at Colliders and Other Probes. Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-319-67606-7_7
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